The present invention relates to a method and apparatus for conditioning the flow of fluid. The invention is believed to have a wide variety of applications, especially in the fabrication and use of calibrated or focused nozzles to create a fluid jet having unique characteristics.
Nozzles are used to create fluid jets in industries such as the oil and gas industry, among other things, to inject and mix fluids and to cleanse and erode surfaces. For example, during oil and gas drilling operations, drilling bits tear away at rock in a well bore while nozzles inject jets of drilling fluid into the well bore. The jets of drilling fluid may be used to assist in the erosion or cleaning of rock from the surface of the well bore by aggressively impinging on the surface. The fluid jets also may be used to clean rock fragments from the teeth of the drill bits.
When a nozzle is used for the purpose of eroding or cleaning a surface, the nozzle creates a fluid flow that impinges upon that surface. In many applications, the fluid flow is a "single-phase" flow in which the fluid flowing through the nozzle is a substantially homogeneous liquid (e.g., water). When pressure is applied to a single-phase fluid in the nozzle, a single-phase fluid jet impinges upon the surface and imparts energy to particles at the surface. Frequently the energy transferred from the fluid jet to the surface particles imparts momentum to the surface particles, thereby separating the particles from the surface. Such a separation of surface particles leads to an erosion or cleaning of the surface.
Improved ability and efficiency in separating the particles from the surface have been achieved through "multi-phase" fluid flow. For example, "dual-phase" flow may occur when gases are introduced into the liquid flowing through the nozzle, and "three-phase" flow may occur when particulate materials are entrained along with gas and/or liquid into the fluid. Multi-phase flow produces different erosion or cleaning characteristics from single-phase flow.
The fluid flow produced by a nozzle also may mix fluids and particles both at and away from an impingement surface. In any fluid flow, the presence of turbulent kinetic energy (i.e., turbulence) creates agitation within the fluid. Agitation produces a mixing phenomenon in the fluid which is beneficial, for example, in combining eroded rock fragments with the flowing fluid, thereby enhancing the ability of rock fragments to be carried out of the drilling area.
While the use of fluid jets generally for eroding, cleaning and mixing is well known in the art, room for improvement exists. For example, energy transfer between fluid jets and impingement surfaces can be carried out with greater efficiency. In addition, agitation created by the presence of turbulent kinetic energy can be increased.